1. Field of the Invention
The present invention relates in general to window regulators of a motor vehicle, and more particularly to power devices, for the window regulators, of a type which drives pull-up and pull-down drive cables for regulating a window pane.
2. Description of the Prior Art
In power devices of the above-mentioned type, there has been employed an arrangement wherein a motor-powered driving part and a cable winder part are detachably connected, so that the motor-powered driving part can be applied to various types of cable winder parts.
In order to clarify the task of the present invention, one conventional power device of the above-mentioned type will be described with reference to FIGS. 5 and 6, which is disclosed in Japanese Patent First Provisional Publication No. 60-80676.
Referring to FIG. 5, motor-powered driving part is shown, which comprises an electric motor A, a speed reduction gear B and an output shaft C. The speed reduction gear B includes a worm which is driven by a drive shaft of the motor A and a worm wheel which is meshed with the worm and drives the output shaft C. The output shaft C has at its exposed end portion three engaging pawls C.sub.1, C.sub.2 and C.sub.3 which are arranged about the axis of the shaft C at equally spaced intervals of 120.degree..
Referring to FIG. 6, a cable winder part is shown, which comprises a drum D for winding thereon pull-up and pull-down drive cables of a window pane. Designated by numeral D.sub.3 is a shaft bore formed in the center of the drum D. The drum D has a spirally turned groove D.sub.1 formed thereabout for neatly winding thereon the pull-up and pull-down drive cables. Designated by numerals D.sub.2 and D.sub.2 are catching cuts which are provided at axially opposed circular portions of the drum D for retaining respective ends of the drive cables. One of the axially opposed circular portions of the drum D is formed with a depressed pattern which comprises an annular groove D.sub.4 coaxially extending about the shaft bore D.sub.3 and three radially extending recesses E.sub.1, E.sub.2 and E.sub.3 arranged on the annular groove D.sub.4 at equally spaced intervals of 120.degree..
Upon assembly, the engaging pawls C.sub.1, C.sub.2 and C.sub.3 of the output shaft C are brought into a meshing engagement with the three recesses E.sub.1, E.sub.2 and E.sub.3 of the drum D to achieve a driving connection between the driving part and the cable winder part.
However, due to its inherent construction, the above-mentioned power device has the following drawbacks which are encountered during assembly procedure of the window regulator.
That is, for assembling the window regulator, the pull-up and pull-down drive cables are fixed at their outward ends to a carrier plate of the window pane which runs upward and downward along a vertically extending guide rail secured to a vehicle door, then the two drive cables are put around upper and lower guide pulleys arranged at upper and lower ends of the guide rail, and then the inward portions of the drive cables are wound around the drum D having the inward ends of the cables retained to the cuts D.sub.2 and D.sub.2 of the drum D. Thereafter, the motor-powered driving part is mounted to the cable winder part which has been thus subassembled. This means that the mounting of the motor-powered driving part to the cable winder part should be made after the cable winder part is fixed to a so-called window pane carrying device. However, this process induces that an assembler must carry out the mounting awkwardly without checking the connection manner of them with his eyes. As is known, this mounting procedure method is difficult or at least troublesome.
In fact, the proper coupling between the output shaft C and the drum D should be made by turning, in a severe case, the drum D by 60.degree. in either direction. However, after fitting the cable winder part to the window panel carrying part, the turning of the drum D can not be easily achieved because of a considerable resistance by the drive cables. Thus, the mating of the two parts sets the assembler a very difficult work.